In the telecommunications industry, there is an on-going requirement to increase the transmission bandwidth so as to allow the delivery of greater communication services such as video, and high density computer data. Single mode optical fibers are known to be an ideal medium for the transmission of wide bandwidth data and, consequently, transmission systems specifically designed to take advantage of this property are continually being developed. Such systems include wavelength division multiplexing (WDM) and time division multiplexing (TDM) photonic networks. In return to zero (RZ) coding and pulse position coding (PPC) the shorter the pulse width of the data train the shorter the time slot and hence the greater the overall capacity of the TDM systems.
Further, in optical information processing and optical computing systems shortening the bit length in the time axis can speed up the processing or computing. It may also provide processing accuracy through precise signal triggering by the short pulses.
The present invention relates to a system wherein ultra short pulses are generated optically by utilizing the output of one semiconductor laser to effect Q-switching of another semiconductor laser. In addition, the system is capable of wavelength conversion between the wavelengths of the two lasers.